Door closers are mounted to hinged doors to urge them towards a closed position. An existing type of door closer comprises an elongate rectangular base plate intended to be fixed towards the top of a door, with a long side parallel to the top of the door. The base plate supports a spring loaded actuator and damper arrangement with a rotary shaft protruding from each end and extending perpendicular to the long sides of the base plate. The shaft is biased towards a stop, and may be rotated against the spring bias away from the stop.
In use, the base plate is affixed to a door. One end of an elongate arm is rotationally connected to the rotary shaft extending from the top of the actuator. The opposite end of the elongate arm is pivotally connected to the end of a second elongate arm, and the opposite end of the second elongate arm is pivotally mounted to the door frame by a bracket. The closer is mounted so that when the door is in a closed position the rotary shaft is held away from its stop so that the resilient bias of the actuator urges the door towards its closed position. As the door is opened, the arms cause the rotary shaft to be further rotated against the resilient bias, so that when the door is released, the actuator effects a controlled closing of the door as the spring urges the rotary shaft back towards its stop, overcoming friction of the damper.
If the door is hung from its left hand side, when facing the side of the door to which the closer is mounted, the closer is mounted to the door with one end of the rotary shaft uppermost. If the door is hung from its right hand side, when facing the side of the door to which the closer is mounted, the closer is mounted to the door with the opposite end of the rotary shaft uppermost so that the actuator urges the shaft to rotate in a direction which causes the door to close.
Therefore, when the closer is mounted to the push side of the door the same end of the closer will be positioned towards the hinged side of the door whether the door is hinged to its left or right side. When the closer is mounted to the pull side of the door the opposite end of the closer will be positioned towards the hinged side of the door, again irrespective as to whether the door it hinged to its left or right side. So the closer is mounted in one of four different orientations depending on which side of a door it is mounted on, and from which side the door is hung.
It is known for door closers to include a latch arrangement which engages when a door is opened to prevent the door closing under the action of the closer. The latch can be released by operation of an electrical solenoid to allow the door to close. Typically, an electrical switch is provided to enable a user to operate the solenoid and allow the door to close. The solenoid may also be operated automatically in the event that a fire alarm system is triggered.
The solenoid is electrically connected to a suitable electrical circuit by an electrical cable which runs downwardly from the underside of the closer adjacent the end of the closer towards the hinged side of the door and follows a U-shaped path to connect to a connection box disposed on the door frame adjacent the hinged side of the door. This enables a short length of cable to be employed as well as limiting stress on the cable through movement of the door.
To accommodate this, existing door closers of this type include four electrical connections, one at each opposite end of each long side of the base plate. This increases the cost and complexity of manufacture. Or, different versions of a door closer are provided depending on the intended installation, which gives rise to inventory control issues in maintaining and selecting from a stock of different types of closer.
The latch arrangement comprises a latch member which may protrude from either of the long sides of the closer, adjacent the rotary shaft. A second latch member is provided on a plate secured to the rotary shaft, for rotation with the shaft, and the two latch members engage to prevent the shaft rotating back when a door has been fully opened. The elongate arm is mounted to the rotary shaft via the plate, and its position may be adjusted relative to the plate in order to determine the angle of opening of the door at which the latch engages to hold the door open. The angle of the elongate arm relative to the plate, and thus the second latch member, varies not only in dependence on the angle at which the door is to be latched open, but also on whether the closer is mounted on the push or pull side of the door.
To accommodate this variation one current door closer is supplied with two different plates and the appropriate plate must be selected according to the manner of its installation. Another current closer is provided with a reversible plate, and the plate must be oriented on the rotary shaft according to the manner of its installation. In both cases this adds complexity to installation. Providing two different types of plates is wasteful as only one is used, or adds complexity to inventory control and supply of the plate if only a selected single plate is supplied with a closer. The reversible plates are effectively a combination of both types of existing plate, and whilst providing a single plate simplifies supply of plates it is still necessary to orient it correctly and additional material is used in producing a double sided plate as opposed to a single plate suited to a particular installation.
Embodiments of the present invention have been made in consideration of these problems.